Receiving apparatus for television



g 1 R. BAR'IHELEMY 2,050,411

RECEIVING APPARATUS FOR TELEVISION Filed Dec. 16, 1931 fien Bar H7 elemINVENTOR 4 ATTORNEY Aug. 11, 19361 RECEIVING srrsns'rns non TELEVISIONRen Barthelemy, Fontenay aux Roses, France, assignor to Compagnie pourla Fabrication des iJOm-pteurs et Materiel dUsines a Gas, Montrouge,France Application December 16, 193i, Serial'No. 581,395 InFrance'Deceinber 20, 193d 7 r V c fluorescent surface which forms thescreen.

The present invention has for itsobiect to 'providean apparatus in whichthe moving lumi:

. nous source will be considerably more intense and in which a cathoderay oscillograph is used in order to cause the movable light source totraverse the screen on which the, image or scene produced is observed.

To this end, the beam of cathode rays in the oscillograph is used as amoving conductor to connect..at a great speed, an electric source to anumber of points disposed on the interior; of the oscillograph, each ofthese points being electricalla connected with the cathode of a tubecon- 7 taming a rare gas maintained at a low pressure.

In this manner the electric discharge set up successively between eachone of the cathodes and the anode of the rarefied gas tube renders eachof the cathodes successively luminous with an intensity proportional tothat of the cathode ray beam, and by causing the intensity of thedirecting fields of the oscillograph to vary in synchronism with thetransmission to be received, one can obtain the synthesis of the imageor scene to be reproduced.

The system will thus comprise a cathode ray tube set up as anoscillograph and provided with means for modulating the cathode ray beamaccording to the variations of current produced in the receiveriiby thereceived transmissions; a tube of rarefied rare gas containing alargenumber of cathodes having extremities or prolongations which projectinto the interior of a cathode ray tube and form a surface swept by thecathode ray beam, the anode of the said rarefied gas F d in such amanner that it does not obstruct the view of the cathodes, and thesource producing the electric discharges between said anode andsuccessive cathodes having such a voltage that the intensity and desiredluminous eiiectsareob The attached drawing shows by way of example andnot oi limitation, one embodiment of the system in which the rare gastube is contiguous to the oscillograph.

Figurelisaplanviewand e 2 is an end view oi the arrangement. As shown inFigure l, I is the cathode ray tube,

(on. 17M) 2 is the rarefied gas tube juxtaposed to the oscillograph i.The oscillograph I comprises a cathode 3 and an anode 4. This anode isprovided with an opening through which passes the oathode ray beamemitted by the cathode 3. The directing fields ofthe oscillograph arehere shown as two rectangularly disposed electro-static fields producedby the two condensers 5 and 6 between which passes the cathode ray beam,which is thus deviated. This beam sweeps the surface I of 10 the wall 9which separates the cathode ray tube i from the rarefied gas tube 2.Said wall 9 is constructed very thin and consists of electricallysemi-conducting material. The surface I0 of the wall 9, which isdisposed in the rarefied gas tube 2, represents the screen on which thereproduced scene or image will appear. Thus, a luminous spot will appearinside the tube 2 on the surface it of the wall 9 opposite the point ofimpact of the cathode ray beam on the surface i in tube I. This tube isalso provided with an anode ll disposed peripherally with respect to thescreen surface li! in order that it shall not obstruct the view of thesurface (FigureZ).

The gas contained in the interior of the tube 2 may be, for example,helium or neon or a mixture of these gases. The pressure in the interiorof the tube 2 depends upon the nature of the gas and is such that thedischarge produces only luminosity of the cathodes. 3Q The electricdischarge between the anode H and the various cathodes constituting thesurface i0 is produced by an electric source ii the voltage of which issuch that the desired luminosity of the said cathode is obtained. Thesource i2 is connected on one hand to the anode Ii and on the other handto the cathode 3 of the cathode ray tube, the cathode .ray beam therebyserving as a moving conductor to connect the source l2 successively tothe various cathodes oi the tube 2.

The brilliancy oi the luminous-spot covering the said cathodes dependsupon the intensity of the discharge current. This intensity in turndepends upon the resistance to the passage of the current ofiered by thecathode ray beam, that is to say, on the intensity of the said beam.Thus, the variations of brllliancy of the cathodes of the tubesnecessary for the synthesis of the images or scenes to bereproduced willbe obtained by modulating the intensity of the cathode ray beam acaccording to the variations of the current produced at the receiver by thetransmission to be received. In the example shown in Figure 1 thismodulation is obtained by interposing in the circuit of the anode i thesecondary of a transformer is,

tion.

the primary of which is traversed by the current setup at the receiverby the transmission to be received. There are thus produced voltagevariations resulting in corresponding variations intlge intensity of thecathode ray beam.

The voltages applied to the terminals of the condensers 5 and 6 are suchthat the cathode ray beam sweeps the surface i in parallel juxtaposedbands. in synchronism with the transmitter. Magnetic fields could beemployed equally well.

The embodiment shown in Figure 1 is not intended to be in any. waylimitative of this inven- The two tubes 9 and 2 may be separated andthe-cathodes of the tube 2 suitably'connected to the difierent points ofthe surface i in the tube 8.

What I claim is:

- I i. In an apparatus for reproducing images and scenes by televisionand telecinematosraphy formed by a cathode ray tube and a luminescentelectric discharge tube forming a continuation of the first mentionedtube, a thin partition of semiconducting material separating said tubes,one

" face of said partition being impinged by the cathode rays and theother forming the cathodic surface of the luminescent tube and thescreen on which the reproduced image is observed, a metallic piecewithinthe int tube and constituting the anode thereof perpendicular tothe mean direction or the cathode rays, said metaliic piece having anopening through which the entire cathodic surface may be observed, asource ofwires to said anode of the luminescent tube and to the cathodeof the cathode ray tube, and a transformer'in the'primary of which flowsthe; received current, the secondary being connected in series incathode-anode circuit of the cathode 5 ray tube.

2. In an apparatus as claimed in claim 1,- in which the said luminescenttube contains an inert gas.

3. In an apparatus for reproducing images and i0 scenes by televisionand telecinematography formed by a cathode ray tube and a luminescentelectric discharge tube forming a continuation of the first mentionedtube, a thin partition of semiconducting material separating said tubes:one 15 said tubular anode being parallel with the mean t direction ofthe cathode rays, the-entire cathodic surface being observable throughsaid tubular anode, a'source'oi. electric voltage directly conv nectedby conductingwires to said tubular anode oi the luminescent tube and tothe cathode of I the cathode ray tube, and a transformer in the primaryof which flows the received current, the

secondary being connected in series in the oathode-anode circuit of thecathode ray' tube. r 1

